A novel approach to prevent spinal cord ischemia: Inoue stent graft with a side branch of small caliber for the reconstruction of the artery of Adamkiewicz

Objectives: Paraplegia remains a serious complication after endovascular repair of thoracic aortic aneurysms, and it has been reported that paraplegia might be due to ischemia of the artery of Adamkiewicz. This study investigates the feasibility of an Inoue stent graft with a side branch of a small caliber for the reconstruction of the intercostal artery branching the artery of Adamkiewicz.

Methods: Branched Inoue stent grafts were implanted into the thoracic aorta and 11th intercostal artery of 5 mongrel dogs. The side branch measured 3 x 5 mm and contained a bare-metal coronary stent for fixing to the intercostal arterial wall. Aortography and selective angiography of the 11th intercostal artery were performed before and immediately after implantation and after 1, 4, 8, and 12 weeks. The luminal diameter of the intercostal artery before implantation was 2.4 +/- 0.3 mm.

Results: All stent grafts were successfully deployed. The main body of the graft did not develop endoleak or migrate, and the side branch remained patent for 12 weeks. Angiography performed 1 week postoperatively revealed smooth flow with slight stenosis (4.2% +/- 1.7%) along the side branches and the intercostal arteries in all dogs. Four weeks postoperatively, however, mild concentric stenosis (38% +/- 16%) along the side branch was observed in 4 of the 5 dogs. The percent stenosis at 8 and 12 weeks was 38% +/- 15% and 33% +/- 11%, respectively; these values were not significantly different from the value at 4 postoperative weeks.

Conclusions: A novel Inoue stent graft with a side branch of small caliber was successfully deployed into the canine thoracic aorta and intercostal artery; the side branch remained patent for 12 weeks. This novel technique may enable endovascular reconstruction of the Adamkiewicz artery.